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    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <div>1</div>
    <div>2</div>
    <div>3</div>
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        //1.传统删除事件
        var divs = document.querySelectorAll('div');
        divs[0].onclick = function () {
            this.onclick = null;
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        //2.removeEventListener删除事件
        div[1].addEventListener('click', fn)
        function fn() {
            alert(22);
            this.removeEventListener('click', fn);
        }


    </script>
</body>

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